This series makes "unpack-objects" capable of streaming large objects to disk. As 6/6 shows streaming e.g. a 100MB blob now uses ~5MB of memory instead of ~105MB. This streaming method is slower if you've got memory to handle the blobs in-core, but if you don't it allows you to unpack objects at all, as you might otherwise OOM. Changes since v14: * Remove "object-file.c: do fsync() and close() before post-write die()" as it's not necessary anymore. It was first introduced in v10 and was no longer in the utility function end_loose_object_common() since v12. We can see the discussion[1]. * Minor grammar/comment etc. fixes throughout. 1. https://lore.kernel.org/git/0b9bc499-18c7-e8ab-5c89-f9e1a98685bc@xxxxxx/ Han Xin (4): unpack-objects: low memory footprint for get_data() in dry_run mode object-file.c: refactor write_loose_object() to several steps object-file.c: add "stream_loose_object()" to handle large object unpack-objects: use stream_loose_object() to unpack large objects Ævar Arnfjörð Bjarmason (2): object-file.c: factor out deflate part of write_loose_object() core doc: modernize core.bigFileThreshold documentation Documentation/config/core.txt | 33 +++-- builtin/unpack-objects.c | 106 +++++++++++++-- object-file.c | 233 ++++++++++++++++++++++++++++---- object-store.h | 8 ++ t/t5351-unpack-large-objects.sh | 76 +++++++++++ 5 files changed, 405 insertions(+), 51 deletions(-) create mode 100755 t/t5351-unpack-large-objects.sh Range-diff against v14: 1: bf600a2fa8 ! 1: 9a776f717d unpack-objects: low memory footprint for get_data() in dry_run mode @@ Commit message d9545c7f465 (fast-import: implement unpack limit, 2016-04-25). Suggested-by: Jiang Xin <zhiyou.jx@xxxxxxxxxxxxxxx> - Signed-off-by: Han Xin <hanxin.hx@xxxxxxxxxxxxxxx> + Signed-off-by: Han Xin <chiyutianyi@xxxxxxxxx> Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@xxxxxxxxx> ## builtin/unpack-objects.c ## 2: a327f484f7 < -: ---------- object-file.c: do fsync() and close() before post-write die() 3: 9bc8002282 ! 2: a1e090d338 object-file.c: refactor write_loose_object() to several steps @@ Commit message Helped-by: Ævar Arnfjörð Bjarmason <avarab@xxxxxxxxx> Helped-by: Jiang Xin <zhiyou.jx@xxxxxxxxxxxxxxx> - Signed-off-by: Han Xin <hanxin.hx@xxxxxxxxxxxxxxx> + Signed-off-by: Han Xin <chiyutianyi@xxxxxxxxx> Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@xxxxxxxxx> ## object-file.c ## @@ object-file.c: static int write_loose_object(const struct object_id *oid, char * - ret = git_deflate_end_gently(&stream); + ret = end_loose_object_common(&c, &stream, ¶no_oid); if (ret != Z_OK) -- die(_("deflateEnd on object %s failed (%d)"), oid_to_hex(oid), -- ret); + die(_("deflateEnd on object %s failed (%d)"), oid_to_hex(oid), + ret); - the_hash_algo->final_oid_fn(¶no_oid, &c); -+ die(_("deflateEnd on object %s failed (%d)"), oid_to_hex(oid), ret); - close_loose_object(fd, tmp_file.buf); - if (!oideq(oid, ¶no_oid)) + die(_("confused by unstable object source data for %s"), + oid_to_hex(oid)); 4: 7c73815f18 = 3: 0ddf912d47 object-file.c: factor out deflate part of write_loose_object() 5: 28a9588f9c ! 4: f9e51d3c68 object-file.c: add "stream_loose_object()" to handle large object @@ Commit message Helped-by: René Scharfe <l.s.r@xxxxxx> Helped-by: Ævar Arnfjörð Bjarmason <avarab@xxxxxxxxx> Helped-by: Jiang Xin <zhiyou.jx@xxxxxxxxxxxxxxx> - Signed-off-by: Han Xin <hanxin.hx@xxxxxxxxxxxxxxx> + Signed-off-by: Han Xin <chiyutianyi@xxxxxxxxx> Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@xxxxxxxxx> ## object-file.c ## 6: dea5c4172b ! 5: 61ae1c1632 core doc: modernize core.bigFileThreshold documentation @@ Documentation/config/core.txt: You probably do not need to adjust this value. -Common unit suffixes of 'k', 'm', or 'g' are supported. +* Stored deflated in packfiles, without attempting delta compression. ++ -+The default limit is primarily set with this use-case in mind. With it ++The default limit is primarily set with this use-case in mind. With it, +most projects will have their source code and other text files delta +compressed, but not larger binary media files. ++ +Storing large files without delta compression avoids excessive memory +usage, at the slight expense of increased disk usage. ++ -+* Will be treated as if though they were labeled "binary" (see ++* Will be treated as if they were labeled "binary" (see + linkgit:gitattributes[5]). e.g. linkgit:git-log[1] and -+ linkgit:git-diff[1] will not diffs for files above this limit. ++ linkgit:git-diff[1] will not compute diffs for files above this limit. ++ -+* Will be generally be streamed when written, which avoids excessive ++* Will generally be streamed when written, which avoids excessive +memory usage, at the cost of some fixed overhead. Commands that make +use of this include linkgit:git-archive[1], +linkgit:git-fast-import[1], linkgit:git-index-pack[1] and 7: d236230a4c ! 6: 5a4782d746 unpack-objects: use stream_loose_object() to unpack large objects @@ Commit message Helped-by: Ævar Arnfjörð Bjarmason <avarab@xxxxxxxxx> Helped-by: Derrick Stolee <stolee@xxxxxxxxx> Helped-by: Jiang Xin <zhiyou.jx@xxxxxxxxxxxxxxx> - Signed-off-by: Han Xin <hanxin.hx@xxxxxxxxxxxxxxx> + Signed-off-by: Han Xin <chiyutianyi@xxxxxxxxx> Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@xxxxxxxxx> ## Documentation/config/core.txt ## @@ Documentation/config/core.txt: usage, at the slight expense of increased disk usage. - * Will be generally be streamed when written, which avoids excessive + * Will generally be streamed when written, which avoids excessive memory usage, at the cost of some fixed overhead. Commands that make use of this include linkgit:git-archive[1], -linkgit:git-fast-import[1], linkgit:git-index-pack[1] and -- 2.36.1
